Not long after the release of 1990 Leaf that forgeries began to pop up at baseball card shows across the nation. The Frank Thomas and Juan Gonzalez cards were the most popular, but the Sammy Sosa, Ken Griffey Jr and even Larry Walker cards have been discovered as forgeries.
There are two keys to spotting the forgeries. First, check the weight of the card stock. Many of the forgeries were printed on much lighter card stock as the real 1990 Leaf cards. Remove the card from the top loader or whatever case the dealer has used. The weight difference will likely be difficult to notice unless you have held your 1990 Leaf Jeff Blauser card lately. The second major telltale is the Leaf and Team logos on the card front. Check those spots under magnification. The original cards were printed in solid ink, the forgeries will be made up of dots.